Results Of Radiofrequency Catheter Ablation Research Articles

Catheter Ablation of Atrial Fibrillation in Patients With Chronic Lung Disease

Chronic lung disease (CLD) is one of the important underlying diseases of atrial fibrillation (AF). The outcomes after radiofrequency catheter ablation of AF in patients with CLD have not yet been reported. We investigated the electroanatomic alterations in pulmonary veins (PVs) in CLD patients with AF and assessed their effect on the outcomes of radiofrequency catheter ablation of AF. We assessed 15 patients who had CLD and underwent radiofrequency catheter ablation of AF. CLD included chronic obstructive pulmonary disease, a tuberculosis-destroyed lung, and interstitial lung disease. For controls, we selected 60 sex-, age-, and procedure era-matched non-CLD patients who received radiofrequency catheter ablation for AF (4 controls for each CLD patient). Eight patients had chronic obstructive pulmonary disease, 6 had a tuberculosis-destroyed lung, and 1 had interstitial lung disease. PV morphology in the affected lung was altered significantly, ie, obliteration, pulling of the PVs toward the destroyed lung, or compensatory bulging of the PV antrum. These alterations were related to arrhythmogenicity in 6 (40%) of 15 patients with CLD. Non-PV foci were more common in the CLD group (4/15, 26.7%) than in the control group (3/60, 5.0%; P=0.025). All non-PV foci were located in the right atrium. The AF recurrence rate in the CLD group (26.7%, 4/15) was similar to that in the control group (18.3%, 11/60; P=0.45). Significant alteration of PV anatomy was related to arrhythmogenicity, and non-PV foci from the right atrium were commonly observed in the CLD group. Radiofrequency catheter ablation can be performed safely for AF in CLD patients with a comparable success rate to that in patients with normal lungs.

Catheter ablation of ventricular tachycardia after left ventricular reconstructive surgery for ischemic cardiomyopathy

After surgical ventricular restoration (SVR) for ischemic cardiomyopathy, ventricular tachycardias (VTs) are an important reason for postoperative morbidity and mortality. The purpose of this study was to elucidate the VT substrate, VT characteristics, and outcome of radiofrequency catheter ablation (RFCA) in patients with VT after SVR. Twelve (3%) of 416 patients referred for RFCA for VT after myocardial infarction in three centers had undergone SVR. After induction of VT, left ventricular (LV) electroanatomical mapping was performed. Ablation target sites were identified by entrainment, substrate, and/or pace mapping. Four (33%) patients presented within the perioperative period with incessant VT, and eight (67%) presented with incessant or recurrent VT late after SVR (VT cycle length 453 ± 102 ms). The region of surgical scar was identified by electroanatomical mapping in 11 patients. Twenty-eight VTs (cycle length 384 ± 95 ms) were induced. The VT exit was bordering the surgical scar in 20 (71%) VTs, of which 15 were at the septal side. All VTs were abolished in five patients: in four only the clinical VTs were abolished, and in one reinducibility was not tested. In two patients, ablation failed after which surgical ablation was performed successfully. During follow-up, three (25%) patients died (nonarrhythmic deaths); all had presented early after SVR. Two (17%) experienced recurrent VT. VT after LV SVR seems to have a bimodal presentation; one-third presented with incessant VT in the acute postoperative phase and had a high mortality. Two-thirds presented late after SVR; in these patients RFCA is usually effective. Successful ablation sites are frequently located at the border of surgical scars and patch material.

Transseptal access and atrial fibrillation ablation guided by intracardiac echocardiography in patients with atrial septal closure devices

Percutaneous positioning of closure devices is a well-established treatment of atrial septal defects (ASDs). However, patients who have undergone the procedure are at increased risk for developing atrial fibrillation (AF), and treatment by catheter ablation is underutilized due to the perceived difficulty of obtaining transseptal access in the presence of the closure device. The purpose of this study was to report the acute and long-term results of radiofrequency catheter ablation of AF in patients with ASD closure devices. Thirty-nine patients (age 54 ± 6 years, 72% males) with drug-refractory AF (33% paroxysmal, 51% persistent, 16% long-standing persistent) and ASD closure devices (82% Amplatzer, 18% CardioSEAL) underwent radiofrequency catheter ablation. A double transseptal access guided by intracardiac echocardiography was obtained in all patients. In 35 of 39 patients (90%), the transseptal access was obtained in a portion of the native septum, whereas in 4 of 39 patients (10%), a direct access through the device was required. The latter group had a significantly longer time for achieving the double transseptal access (73.6 ± 1.1 minutes vs. 4.3 ± 0.4 minutes, P < .001), longer fluoroscopy time (122 ± 5 minutes vs. 80 ± 8 minutes, P < .001), and total procedural time (4.1 ± 0.2 hours vs. 3.1 ± 0.3 hours, P < .001). At follow-up of 14 ± 4, months the overall success rate was 77% (85% in paroxysmal AF, 73% in nonparoxysmal AF). Transthoracic contrast-enhanced echocardiography with the Valsalva maneuver, performed between 3 and 6 months after the procedure, failed to detect shunt in all patients. Radiofrequency catheter ablation of AF is feasible, safe, and effective in patients with ASD closure devices. Transseptal access can be obtained in portions of the native septum in the majority of cases. Direct transseptal puncture of the device is feasible and safe but requires longer time for each transseptal access.

Premature ventricular contractions originating from the left ventricular septum: Results of Radiofrequency Catheter Ablation in twenty patients

BackgroundRFCA has been established as an effective and curative therapy for severely symptomatic PVC from the outflow tract in structurally normal hearts. However, it is unknown whether PVCs originating from the left ventricular septum, are effectively eliminated by RFCA. This study aimed to investigate electrophysiologic characteristics and effects of Radiofrequency catheter ablation (RFCA) for patients with symptomatic premature ventricular contraction (PVC) originating from the left ventricular septum without including fascicular PVCs.MethodsCharacteristics of body surface electrocardiogram (ECG) and electrophysiologic recordings endocardiogram in a successful RFCA target were analyzed in 20 patients with symptomatic PVCs originating from the left ventricular septum. RFCA was performed using pace mapping and activation mapping.ResultsThe QRS morphology of PVCs originating from the left ventricular septum is similar to that seen in fascicular tachycardia. Most of the PVCs originated from the left septum appears in the form of ventricular parasystole. The incidence of ventricular parasystole was 70%. Sustained ventricular tachycardia was not inducible by electrical stimulation and isoproterenol infusion in all 20 patients, ablation at the site recording the earliest Purkinje potential was not effective in all 20 patients, and Purkinje potentials were not identified at successful sites during point mapping. Sixteen patients were successful with RFCA using pace mapping and activation mapping, 3 failed, and 1 recurrent.ConclusionAlthough the ECG characteristics of the PVCs arising from the left ventricular septum are similar to that seen in fascicular tachycardia, the electrophysiologic characteristics are different between the two types of PVCs. The distinguishing characteristic of the PVCs is that Purkinje potentials were not present at the site of successful ablation, suggesting a myocardial as opposed to fascicular substrate. RFCA is an effective curative therapy for symptomatic PVCs originating from the left ventricular septum (not from the left anterior and posterior fascicle).

Respiratory cycle–dependent atrial tachycardia: Prevalence, electrocardiographic and electrophysiologic characteristics, and outcome after catheter ablation

Little is known about the tachyarrhythmias relating to respiration. Case reports presented patients with respiratory cycle-dependent atrial tachycardias (RCATs), which cyclically emerge after starting inspiration and cease during expiration. The aim of the present study was to elucidate the prevalence, characteristics, and long-term outcome after radiofrequency catheter ablation (RFCA) of RCATs. The electrocardiographic and electrophysiologic properties and results of RFCA were analyzed in 60 patients with a total of 71 focal atrial tachycardias (ATs). Nine RCATs (13%) were observed in 7 patients (12%). RCATs were irregular, with a mean cycle length ranging from 220 to 650 ms, and developed incessantly accounting for 32% ± 14% of the 24-hour heartbeats. The P-wave morphology was positive or biphasic (positive to negative) in V1, and positive in I and II. The electroanatomical mapping demonstrated a centrifugal activation pattern, with the earliest site located at the antrum of the right superior pulmonary vein (RSPV), inside the RSPV, and inside the superior vena cava (SVC) in 4, 2, and 3 RCATs, respectively. Radiofrequency energy delivery at the earliest site or the electrical isolation of the RSPV and SVC suppressed all RCATs. During a follow-up of 25 ± 15 months, 1 RCAT recurred and was eliminated in a second procedure. RCATs were observed in 13% of the focal ATs. As presumed from the P-wave morphologies, their foci converged around the RSPV or inside the SVC. RFCA was effective to eliminate RCATs.

Impact of left atrial fibrosis and left atrial size on the outcome of catheter ablation for atrial fibrillation

BackgroundLeft atrial (LA) dilatation is an important risk factor for recurrence of atrial fibrillation (AF) after radiofrequency catheter ablation (RFCA). However, the clinical applications to select patients eligible for RFCA...

Effect of Pulmonary Vein Anatomy and Left Atrial Dimensions on Outcome of Circumferential Radiofrequency Catheter Ablation for Atrial Fibrillation

Multislice computed tomography (MSCT) is commonly acquired before radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF) to plan and guide the procedure. MSCT allows accurate measurement of the left atrial (LA) and pulmonary vein (PV) dimensions and classification of the PV anatomy. The aim of the present study was to investigate the effect of LA dimensions, PV dimensions, and PV anatomy on the outcome of circumferential RFCA for AF. A total of 100 consecutive patients undergoing RFCA for AF (paroxysmal 72%, persistent 28%) were studied. The LA dimensions, PV dimensions, and PV anatomy were evaluated three dimensionally using MSCT. The PV anatomy was classified as normal or atypical according to the absence/presence of a common trunk or additional veins. After a mean follow-up of 11.6 ± 2.8 months, 65 patients (65%) maintained sinus rhythm. The enlargement of the left atrium in the anteroposterior direction on MSCT was related to a greater risk of AF recurrence. No relation was found between the PV dimensions and the outcome of RFCA. In addition, normal right-sided PV anatomy was related to a greater risk of AF recurrence compared to atypical right-sided PV anatomy. Multivariate analysis showed that an anteroposterior LA diameter on MSCT (odds ratio 1.083, p = 0.027) and normal right-sided PV anatomy (odds ratio 6.711, p = 0.006) were independent predictors of AF recurrence after RFCA. In conclusion, enlargement of the anteroposterior LA diameter and the presence of normal anatomy of the right PVs are independent risk factors for AF recurrence. No relation was found between the PV dimensions and outcome of RFCA.

The Long-Term Clinical Outcomes of Radiofrequency Catheter Ablation for Inducible Ventricular Tachycardia prior to Implantation of Cardioverter-Defibrillator

Objective: Radiofrequency catheter ablation (RFCA) for inducible ventricular tachycardia (VT) reduces the incidence of implantable cardioverter-defibrillator (ICD) therapy. However, whether RFCA improves long-term outcome of patients receiving ICD remains unknown. Methods: We retrospectively reviewed long-term outcomes of 43 consecutive patients receiving ICD for sustained VT, in whom inducible VT had been documented by electrophysiological studies. Fourteen patients underwent adjunctive RFCA before defibrillator implantation (Group 1), and 29 received defibrillator implantation alone (Group 2). Clinical records were searched for adverse events, including deaths, re-hospitalization, and ICD therapy. Results: Baseline left ventricular ejection fraction (Group 1 vs. Group 2, 43±14% vs. 49±15%, p=0.2) and follow-up periods (1297±911 days vs. 1735±904 days, p=0.15) were not different between two groups. The only significant difference between the groups was with history of VT (10 vs. 9, p=0.02). All death was not significant different (2 (15%) vs. 7 (24%), p=0.7). Re-hospitalization due to cardiac was not different (8 vs. 13, p=0.5). Six patients (43%) received ICD appropriate therapy in Group 1, and 8 (26%) in Group 2 (p=0.5). Conclusion: The current study demonstrated that prophylactic RFCA for inducible VT prior to defibrillator implantation did not provide improved long-term benefits compared with ICD therapy alone in patients with sustained VT. The performance of adjunctive RFCA for patients receiving ICD may require further clarifications.

The Relationship between Internal Cardioversion Threshold or Post-Cardioversion Sinus Node Recovery Time and Atrial Structural or Autonomic Neural Remodeling in Persistent Atrial Fibrillation

Background: We hypothesized that cardioversion (CV) threshold and post-CV sinus node recovery time (PC-SNRT) are related with cardiac autonomic nerve function or atrial structural remodeling in persistent atrial fibrillation (PeAF). Methods: We included 74 patients with PeAF (62 males, 54.8±10.5 years old) who underwent radiofrequency catheter ablation (RFCA) and maintained sinus rhythm at the time of 3rd month Holter without taking any anti-arrhythmic drug or beta-blocker. At the beginning of RFCA, we delivered internal CV 2, 3, 5, 7, and 10 J serially, and measured CV threshold and PC-SNRT. Results: 1. The patients with CHADS2 score >=1 showed higher CV threshold than those with 0 (8.3±2.1 J vs. 6.2±2.5 J, p=0.034). 2. CV threshold of the patients with left atrial (LA) volume >=120 mL was significantly higher than those of patients with =45 mm) by echocardiography were significantly longer than that of the patients with <45 mm (1422.2±1031.7 ms vs. 1060.2±448.2 ms, p=0.05). 4. PC-SNRT was correlated with 3rd month heart rate variability (HRV) including SDNN (R=0.400, p=0.005), HF (R=0.480, p=0.001), but not related with clinical recurrence of AF after RFCA. Conclusion: Both CV threshold and PC-SNRT were significantly greater in patients with atrial structural remodeling, but were not related with clinical outcome of RFCA in PeAF.

Concomitant chronic kidney disease increases the recurrence of atrial fibrillation after catheter ablation of atrial fibrillation: A mid-term follow-up

Chronic kidney disease (CKD) is often associated with atrial fibrillation (AF). However, its impact on the results of radiofrequency catheter ablation for AF has not been fully examined. The purpose of this study was to clarify the relationship between CKD and postcatheter ablation AF recurrence. The study included 221 patients with AF who underwent successful catheter ablation. The prevalence and characteristics of AF recurrences were determined. CKD was defined as an estimated glomerular filtration rate <60 mL/min/1.73 m(2). After mean follow-up of 31.9 ± 7.6 months, 87 (39%) patients had AF recurrences. Multivariate Cox regression analysis revealed that CKD (hazard ratio [HR] 2.089, 95% confidence interval [CI] 1.292-3.378, P <.01) and left atrial volume (HR 1.009, 95% CI 1.002-1.017, P <.05) were independent predictors of AF recurrences. Among the 221 patients, 54 (24.4%) had CKD. Patients with CKD had a higher incidence of AF recurrences (57.4%) compared to the non-CKD patients (33.5%, P <.01). Compared with patients without CKD, patients with CKD were older (64 ± 11 years vs 58 ± 10 years, P <.001) and had a higher prevalence of hypertension (72% vs 53%, P <.05), larger left atrial volume (74.7 ± 29.4 mL vs 62.0 ± 26.0 mL, P <.01), and higher plasma B-type natriuretic peptide levels (129.6 ± 209.3 pg/mL vs 68.8 ± 91.0 pg/mL, P <.01). The presence of CKD increased the risk of AF recurrences after catheter ablation. Multifactorial physiologic factors due to CKD may account for the higher prevalence of recurrent AF in patients with CKD than in those without.

Outcome of Intra-Atrial Re-Entrant Tachycardia Catheter Ablation in Adults With Congenital Heart Disease: Negative Impact of Age and Complex Atrial Surgery

The aim of this study was to determine the acute and long-term outcome of radiofrequency catheter ablation (RFCA) for intra-atrial re-entrant tachycardia (IART) in adults with congenital heart disease (CHD), and predictors of these outcomes. Atrial myopathy can be progressive in CHD and contributes to the substrate for IART. Although the outcome of RFCA for IART has been well described in children and adolescents with CHD, it is unclear whether these results are similar in the adult population. Clinical records of adults with CHD undergoing attempted RFCA of IART were analyzed retrospectively. Multivariate analyses identified clinical and procedural factors that predicted acute and long-term outcomes. A total of 193 procedures was performed in 130 patients (mean age 40 ± 13 years); 82 of 118 (69%) initially attempted RFCA were successful, defined as termination of all IART circuits. The use of electroanatomic mapping was associated with a successful RFCA, whereas Fontan palliation and Mustard repair were associated with an unsuccessful RFCA. Median clinical follow-up of 77 patients (≥2 months of follow-up) after a successful RFCA was 3.7 years (range 0.2 to 10.2 years). IART recurrence was noted in 48%, cardioversion/reablation in 42%, and death in 4%. Older age and Fontan palliation were independent predictors of IART recurrence. In adults with CHD, acute and long-term outcomes of RFCA for IART are similar to those reported for younger cohorts. Complex atrial surgery limits the success of RFCA, and older age is associated with a higher risk of IART recurrence.

E0551 Radiofrequency catheter ablation of ventricular tachycardia in patients with structural heart diseases using CARTO electroanatomic mapping system and a salineirrigated tip catheter

IntroductionThe aim of this study was to investigate the results of radiofrequency catheter ablation of ventricular tachycardia (VT) in patients with organic heart diseases utilising CARTO system and a saline-irrigated...

The Relationship Between Endocardial Voltage and Regional Volume in Electroanatomical Remodeled Left Atria in Patients with Atrial Fibrillation: Comparison of Three‐Dimensional Computed Tomographic Images and Voltage Mapping

Long-standing atrial fibrillation (AF) changes left atrial (LA) morphology, and the LA size is related to recurrence after radiofrequency catheter ablation (RFCA). We hypothesize that LA morphology, based on embryological origin, affects the outcome of RFCA. We analyzed 3D computed tomographic (CT) images of LA in 70 patients with AF (54 males, 55.6 +/- 10.5 years old, paroxysmal AF (PAF):persistent AF (PeAF) = 32:38) who underwent RFCA. Each LA image was divided into venous atrium (VA), anterior LA (ALA), LA appendage (LAA), and both antrum. Absolute and relative volumes were calculated, and the lengths of linear ablation sites were measured. (1) In patients with the mean LA voltage < or = 2.0 mV, LA volume, especially ALA, was larger (P < 0.01) compared to those with LA voltage > 2.0 mV. (2) The total LA volume was significantly larger (P < 0.01) and LAA voltages (P < 0.05) and conduction velocities (P < 0.05) were lower in patients with PeAF than in those with PAF. (3) In patients with recurrence, LA volume was generally larger (P < 0.01) than in those without recurrence. In PAF patients with recurrence, the relative volume of ALA was significantly larger (P < 0.01) than those without recurrence. Morphologically remodeled LA has low endocardial voltage, and enlargement of ALA is more significant in electroanatomically remodeled LA. The disproportional enlargement of ALA was observed more often in PAF patients with recurrence after ablation than those without recurrence.

Outcome of Radiofrequency Catheter Ablation as a non-pharmacological therapy for idiopathic Ventricular Tachycardia.

To determine the outcome of Radiofrequency Catheter Ablation (RFCA) as a non-pharmacological curative therapy for idiopathic Ventricular Tachycardia (VT) and to identify procedure-related complications. Descriptive study. The Armed Forces Institute of Cardiology and National Institute of Heart Diseases, Rawalpindi, from February 2001 to October 2008. Ninety eight consecutive patients with idiopathic VT, resistant to drug therapy, who underwent Electrophysiology Studies (EPS) radiofrequency catheter ablation were enrolled. Clinical and electrophysiological variables were recorded and a descriptive analysis was done. Out of the 98 patients, 79 were males (80.6%). The mean age was 33.29+11.93 years. Modes of presentation were sustained VT, Repetitive Monomorphic VT (RMVT), Non-sustained VT (NSVT) and Ventricular Premature Beats (VPBs). Right Ventricular Outflow Tract (RVOT) VT was found in 37 patients, 37 had Idiopathic Left Ventricular Tachycardia (ILVT), 20 had Left Ventricular Outflow Tract (LVOT) VT, and Inflow Right Ventricular Tachycardia (IRVT) was found in 7 patients. Other sites of origin of VT were infrequent. Eight patients had dual morphologies of VT. Atrioventricular Nodal Re-entry Tachycardia (AVNRT) was found in 8 patients. RFCA was successful in abolishing inducible VT in 88 patients. One patient developed complete AV block requiring a permanent pacemaker. Results of this study confirm a high degree of success and safety of radiofrequency catheter ablation as curative therapy for idiopathic ventricular tachycardia.

Radiofrequency Catheter Ablation of Supraventricular Tachycardia in Infants and Toddlers

The role of radiofrequency catheter ablation (RFCA) of supraventricular tachycardia (SVT) in infants and toddlers is still unclear. From 1993 to 2006, 27 (17 males, 10 females) of 210 patients underwent RFCA at an age less than 6 years. Indications included drug-refractory SVT or tachycardia-induced cardiomyopathy. The medical records were reviewed and the patients were interviewed regarding their current status. The 27 patients underwent RFCA at a median age of 4.4 years (8 months to 5.9 years) and a median body weight of 15 kg (6.6-30 kg). The SVT was mainly atrioventricular reentry tachycardia (15/27) and multiple mechanisms in 3. One-third of them had associated congenital heart disease, and 5 underwent RFCA using only 2-3 catheters. Immediate success rate was 92.6%, with low early (3.7%) and late recurrence (7.4%) after 5.4 +/-3.7 years follow-up. Tachycardia-induced cardiomyopathy was noted in 4 and resolved in all after RFCA. Procedure-related complications included complete atrioventricular block in 1 and Bezold-Jarisch reflex in another. No other risk factors for outcomes were noted, even with low body weight. The outcome of RFCA for medically refractory SVT, even associated with tachycardia-induced cardiomyopathy, in infants and toddlers is favorable.

Idiopathic Ventricular Arrhythmias Originating From the Aortic Root: Prevalence, Electrocardiographic and Electrophysiologic Characteristics, and Results of Radiofrequency Catheter Ablation

This study investigated the prevalence and electrocardiographic and electrophysiologic characteristics of aortic root ventricular arrhythmias (VAs). Idiopathic VAs originating from the ostium of the left ventricle may be ablated at the base of the aortic cusps. We studied 265 patients with idiopathic VAs with an inferior QRS-axis morphology. The successful ablation site was within (or below) the aortic cusps in 44 patients (16.6%). The site of the origin was the left coronary cusp (LCC) in 24 (54.5%), the right coronary cusp (RCC) in 14 (31.8%), the noncoronary cusp (NCC) in 1 (2.3%), and at the junction between the LCC and RCC (L-RCC) in 5 (11.4%) cases. The maximum amplitude of the R-wave in the inferior leads was significantly greater with an LCC than with an RCC origin (p < 0.05). The ratio of the R-wave amplitude in leads II and III was significantly greater with an LCC than with an RCC origin (p < 0.01) and was significantly smaller in the NCC than in the other sites (p < 0.0001). The ventricular deflection in the His bundle electrogram was significantly later relative to the surface QRS with an LCC or L-RCC origin than with an RCC or NCC origin (p < 0.0001). The ratio of the atrial-to-ventricular deflection amplitude was significantly greater in the NCC than in the other sites (p < 0.0001). No other factors predicted the site of origin. Idiopathic VAs are more common in the LCC than in the RCC and rarely arise from the NCC. The electrocardiogram is useful for differentiating the site of origin.

Body Mass Index, Obstructive Sleep Apnea, and Outcomes of Catheter Ablation of Atrial Fibrillation

Obesity and obstructive sleep apnea (OSA) are associated with atrial fibrillation (AF). The effects of a large body mass index (BMI) and OSA on the results of radiofrequency catheter ablation (RFA) of AF are unclear. To evaluate the effect of BMI and OSA on the efficacy of RFA for AF. RFA was performed in 324 consecutive patients (mean age = 57 +/- 11 years) with paroxysmal (234) or chronic (90) AF. OSA was diagnosed by polysomnography in 32 of 324 patients (10%) prior to ablation. Among the 324 patients, 18% had a normal BMI (<25 kg/m(2)), 39% were overweight (BMI >/= 25 kg/m(2) and <30 kg/m(2)), and 43% were obese (>or=30 kg/m(2)). RFA was performed to eliminate complex fractionated atrial electrograms (CFAE) in the pulmonary vein antrum and left atrium. At 7 +/- 4 months after a single ablation procedure, 63% of patients without OSA and 41% with OSA were free from recurrent AF without antiarrhythmic drug therapy (P = 0.02). Multivariate analysis including variables of age, gender, type and duration of AF, OSA, BMI, left atrial size, ejection fraction, and hypertension demonstrated that OSA was the strongest predictor of recurrent AF (OR = 3.04, 95% CI: 1.11-8.32, P = 0.03). There was no association between BMI and freedom from recurrent AF. A serious complication occurred in 3 of 324 patients, with no relationship to BMI. OSA is a predictor of recurrent AF after RFA independent of its association with BMI and left atrial size. Obesity does not appear to affect outcomes after radiofrequency catheter ablation of AF.

Radiofrequency atrial fibrillation ablation based on pathophysiology: a diversified protocol with long-term follow-up

The optimal approach and long-term results of radiofrequency catheter ablation of atrial fibrillation (AF) are still unknown. We report our experience with respect to an ablation protocol diversified on a patient's AF pathophysiology with long-term follow-up. Seventy-two patients with paroxysmal/persistent drug-resistant AF were selected. Patients with apparently normal hearts (group 1, n = 20) underwent electrophysiological disconnection of pulmonary veins (PVs) presenting a clear PV potential, whereas those with even initial cardiopathy (group 2, n = 52), underwent PV encircling. Sinus rhythm was maintained at 6 months in 85% of group 1 and 71% of group 2 patients. After 42 months of follow-up, including 15.2% re-do procedures, 85% of group 1 and 77% of group 2 patients were in sinus rhythm, including patients with anti-arrhythmic drugs (AADs). The long-term success rate without AADs was 75% and 46% for each group, respectively. Age and the 6-month success of the procedure were predictive of sinus rhythm maintenance during follow-up. An ablation protocol diversified on AF pathophysiology assured, at 3 years of follow-up, sinus rhythm maintenance in 85% of patients with a normal heart and in 77% of those with even initial cardiopathy. The 6-month result of the ablation procedure remained stable over time.

Mounting Evidence That Fibrosis Generates a Major Mechanism for Atrial Fibrillation

See related article, pages 839–847 It is widely known that atrial fibrillation (AF) is the most common sustained cardiac arrhythmia, with the problem magnified by the clinical sequelae; eg, thromboembolic events. It is pertinent that the incidence of AF is expected to increase in the future,1 especially in aging patients. Thus, finding preventive measures for this arrhythmia has become an increasingly important goal. In addition to considering clinical risk factors, focusing on prevention necessitates knowledge of the associated pathophysiology of AF,2 which involves the initiation of AF and the wavefront dynamics that sustain it. In recent years considerable new information has appeared concerning AF mechanisms that occur in different regions of the atria in different cardiac states.3 This point is highlighted by the report of Tanaka et al4 in this issue of Circulation Research . These authors used high-resolution electrophysiological and microstructural techniques, along with computer model simulations, to study wavefront dynamics during acetylcholine (ACh)-induced AF in heart failure sheep hearts. The heart failure hearts had developed prominent fibrotic patches in the posterior left atrium near the pulmonary veins, whereas in the control (normal) hearts patches of fibrosis were smaller, diffusely distributed, and more centrally located with respect to the 4 pulmonary vein ostia. In the heart failure hearts, during AF variable wavefront breakthroughs to the endocardium occurred in the area of fibrotic patches adjacent to the pulmonary veins. The authors concluded that scroll waves within the posterior left atrial wall produced a microreentry source for the endocardial breakthroughs in the region of the larger collagen patches, thus providing the underlying mechanism of AF.4 A myriad of reports provide varied information about substrates and mechanisms of AF as a background for the study of Tanaka et al …

Long-Term Efficacy of Catheter Ablation of Ventricular Tachycardia in Patients With Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy

This study sought to evaluate the outcomes of radiofrequency catheter ablation (RFA) of ventricular tachycardia (VT) in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) patients. Particular focus was placed on defining the single-procedure efficacy over long-term follow-up. ARVD/C is an inherited cardiomyopathy characterized by VT and right ventricular dysfunction. Prior single-center studies have reported conflicting results concerning the efficacy of RFA of VT in ARVD/C patients. The study population comprised 24 patients (age 36 +/- 9 years, 11 male), enrolled in the Johns Hopkins ARVD registry, who underwent 1 or more RFA procedures for treatment of VT. Patients were followed up for 32 +/- 36 months (range 1 day to 12 years). Recurrence was defined as the documentation of VT subsequent to the procedure. A total of 48 RFA procedures were performed using 3-dimensional electroanatomical (n = 10) or conventional (n = 38) mapping. Of these procedures, 22 (46%), 15 (31%), and 11 (23%) resulted in elimination of all inducible VTs, clinical VT but not all, and none of the inducible VTs, respectively. Forty (85%) procedures were followed by recurrence. The cumulative VT recurrence-free survival was 75%, 50%, and 25% after 1.5, 5, and 14 months, respectively. The cumulative VT recurrence-free survival did not differ by procedural success, mapping technique, or repetition of procedures. There was 1 procedure-related death. Our study shows a high rate of recurrence in ARVD/C patients undergoing RFA of VT. This likely reflects the fact that ARVD/C is a diffuse cardiomyopathy with progressively evolving electrical substrate. Further studies are needed to define the precise role of RFA of VT in ARVD/C.